Technical Field
The present disclosure relates generally to turbo charger systems for internal combustion engines. More specifically, the present disclosure relates to a multi-stage turbo charger system with continuous feedback control.
Background
In turbo-charged engines with multiple turbo chargers (usually two), it is desirable that the turbo chargers operate together efficiently in view of changing engine operating conditions (e.g. speed, load, etc.). Many multi-stage turbo systems do not achieve this. One challenge is that the operation of the wastegate is sometimes not controlled in a way that keeps the turbo compressors operating at desired efficiency. For example, on/off-type controllers have been used, but these often do not produce desired results. While systems exist that can keep one of the turbo system parameters (e.g. a single pressure) at a constant value, this does not guarantee a pressure ratio for high efficiency.